High transparency electrochromic polymers

ABSTRACT

An electrochromic polymer is comprised of a repeat unit comprising one or more meta-conjugated linkers (MCLs) and one or more aromatic moieties (Ars). Each of the one or more MCLs is partially conjugated with the one or more Ars at meta positions of the MCLs to form a polymer backbone of the electrochromic polymer. The electrochromic polymer undergoes an optical switching and a color change in an electrochromic device, which shows a high transparency and a high optical contrast.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation-In-Part application ofNon-Provisional application Ser. No. 17/668,300, filed on Feb. 9, 2022,the entire content of which is incorporated herein by reference in itsentirety.

TECHNICAL FIELD

The present disclosure is related to a new type of electrochromicpolymers that comprise meta-conjugated linkers and aromatic moieties,which present a high transparency in the visible light region in theneutral state. The polymers become highly absorbing in the visible lightand near-infrared region and thus colored when their films are beingoxidized. A device incorporating such conjugated electrochromic polymerfilms with a high optical contrast and a high transmittance is alsodisclosed.

BACKGROUND

Electrochromic devices allow to adjust light transmittance and controlsolar-heat gain. In comparison with inorganic-based electrochromicdevices made through the vacuum sputtering process, polymer-basedelectrochromic windows can be manufactured through roll-to-roll coatingand lamination. It thus renders a low-cost production and manufacturingflexibility. Polymer based electrochromic devices are typically composedof conjugated electrochromic polymers (ECPs), which feature fullyconjugated polymer backbone made of sp² hybridized carbons.Conventionally, ECPs typically have strong absorbance in the visiblelight region and are thus colored in their neutral state. When they areoxidized, their absorption is shifted toward near-infrared (near-IR)region and they become transmissive in the visible light region.However, the oxidized polymers still have weak absorption in the visiblelight region, leading to residue colors. The problem becomes more severewhen the polymer films are thick. As a result, it negatively impactsoptical contrast of the polymers. Furthermore, it limits the highestoptical transmittance an electrochromic conjugated polymer can achieve.In addition, conventional ECPs in the neutral state blocks visible lightthrough the film and allow near-IR light passing through; While in thetransmissive state, it allows visible light passing through and blocksnear-IR light. This combination is not effective for thermal managementand control the solar-heat gain (SHG). SHG describes the way radiationfrom the sun is turned into heat through a window product.

SUMMARY

The present disclosure is related to a new type of electrochromicpolymer. The disclosed polymer backbone comprises a repeat unitcomprising one or more meta-conjugated linkers (MCLs) and one or morearomatic moieties (Ars). Each of the one or more MCLs is partiallyconjugated with the one or more Ars at meta positions of the one or moreMCLs to form the polymer backbone of an electrochromic polymer. In someembodiments, the electrochromic polymer is anodically-coloringelectrochromic polymer (AC-ECP), becoming colored when it is oxidized.

In some embodiments, the electrochromic polymer has an absorption onset(

_(c), the wavelength at higher than which the polymer has no photonabsorption) at 480 nm or less in the neutral state. In some embodiments,the electrochromic polymer has an absorption onset at 450 nm or less inthe neutral state. In some embodiments, the electrochromic polymer hasan absorption onset at 400 nm or less in the neutral state. In someembodiments, the absorption maxima (

_(max), the wavelength at which the polymer has its strongest photonabsorption) are less than 420 nm in the neutral state. In someembodiments, the electrochromic polymer is colorless or yellow in theneutral state, while it is colored and visible and near-infraredabsorbing in the oxidized state. The oxidized electrochromic polymer hasan absorption coefficient larger than 10⁴ cm⁻¹ in the visible and/ornear-IR region and thus colored in the oxidized state.

In spite of their high bandgaps, the disclosed ECPs still haverelatively low oxidation potential in the ranges of 0.1-1.5 V inclusiveversus Ag/AgCl electrode in some embodiments.

The MCL comprises at least one of an aromatic ring structure, or a fusedaromatic ring structure, or the combinations thereof. The aromaticstructure comprises a benzene or heterocyclic structure. The fusedaromatic ring comprises a fused benzene structure or a fusedheterocyclic structures or a fused benzene and heterocyclic ringstructure.

In some embodiments, for the disclosed ECPs, the MCLs and the Ars arearranged in an alternative or random fashion with a general formula of

In the structures here, each of n and m₁, m₂, . . . , m_(n) is aninteger higher than 0. The MCLs (or Ars) can be the same as or differentfrom each other.

In some embodiments, the MCL and its meta-positions comprise

wherein each of the wavy lines represents meta-positions to linkadjacent Ar units; X is S, Se, N, C, or O; R₁-R₁₂ is independentlyselected from the following substituents, including, but not limited to,hydrogen, C₁-C₃₀ alkyl, C₂-C₃₀ alkenyl, C₂-C₃₀ alkynyl, C₂-C₃₀alkylcarbonyl, C₁-C₃₀ alkoxy, C₃-C₃₀ alkoxyalkyl, C₂-C₃₀ alkoxycarbonyl,C₄-C₃₀ alkoxycarbonylalkyl, C₁-C₃₀ alkylthio, C₁-C₃₀ aminylcarbonyl,C₄-C₃₀ aminylalkyl, C₁-C₃₀ alkylaminyl, C₁-C₃₀ alkylsulfonyl, C₃-C₃₀alkylsulfonylalkyl, C₆-C₁₈ aryl, C₃-C₁₅ cycloalkyl, C₃-C₃₀cycloalkylaminyl, C₅-C₃₀ cycloalkylalkylaminyl, C₅-C₃₀ cycloalkylalkyl,C₅-C₃₀cycloalkylalkyloxy, C₁-C₁₂ heterocyclyl, C₁-C₁₂ heterocyclyloxy,C₁-C₃₀ heterocyclylalkyloxy, C₁-C₃₀ heterocyclylaminyl, C₅-C₃₀heterocyclylalkylaminyl, C₂-C₁₂ heterocyclylcarbonyl, C₃-C₃₀heterocyclylalkyl, C₁-C₁₃ heteroaryl, or C₃-C₃₀ heteroarylalkyl.

In some embodiments, an Ar comprises one of a thiophene-based unit, afuran-based unit, a selenophene-based unit, or a pyrrole-based unitrespectively with a formula of

or any combination thereof,wherein each of R₁₃ and R₁₄ is independently selected from the followingsubstituents, including, but not limited to, hydrogen, C₁-C₃₀ alkyl,C₂-C₃₀ alkenyl, C₂-C₃₀ alkynyl, C₂-C₃₀ alkylcarbonyl, C₁-C₃₀ alkoxy,C₃-C₃₀ alkoxyalkyl, C₂-C₃₀ alkoxycarbonyl, C₄-C₃₀alkoxycarbonylalkyl,C₁-C₃₀ alkylthio, C₁-C₃₀ aminylcarbonyl, C₄-C₃₀ aminylalkyl,C₁-C₃₀alkylaminyl, C₁-C₃₀ alkylsulfonyl, C₃-C₃₀ alkylsulfonylalkyl,C₆-C₁₈ aryl, C₃-C₁₅ cycloalkyl, C₃-C₃₀ cycloalkylaminyl, C₅-C₃₀cycloalkylalkylaminyl, C₅-C₃₀ cycloalkylalkyl, C₅-C₃₀cycloalkylalkyloxy,C₁-C₁₂ heterocyclyl, C₁-C₁₂ heterocyclyloxy, C₁-C₃₀heterocyclylalkyloxy, C₁-C₃₀ heterocyclylaminyl, C₅-C₃₀heterocyclylalkylaminyl, C₂-C₁₂ heterocyclylcarbonyl, C₃-C₃₀heterocyclylalkyl, C₁-C₁₃ heteroaryl, or C₃-C₃₀ heteroarylalkyl.

In some embodiments, the thiophene-based unit comprises a formula of

combination thereof,wherein X is S, Se, N, C, or O; each of R₁₅-R₁₈ is independentlyselected from the following substituents, including, but not limited to,hydrogen, C₁-C₃₀ alkyl, C₂-C₃₀ alkenyl, C₂-C₃₀ alkynyl, C₂-C₃₀alkylcarbonyl, C₁-C₃₀ alkoxy, C₃-C₃₀ alkoxyalkyl, C₂-C₃₀ alkoxycarbonyl,C₄-C₃₀ alkoxycarbonylalkyl, C₁-C₃₀ alkylthio, C₁-C₃₀ aminylcarbonyl,C₄-C₃₀ aminylalkyl, C₁-C₃₀alkylaminyl, C₁-C₃₀ alkylsulfonyl, C₃-C₃₀alkylsulfonylalkyl, C₆-C₁₈ aryl, C₃-C₁₅ cycloalkyl, C₃-C₃₀cycloalkylaminyl, C₅-C₃₀ cycloalkylalkylaminyl, C₅-C₃₀ cycloalkylalkyl,C₅-C₃₀cycloalkylalkyloxy, C₁-C₁₂ heterocyclyl, C₁-C₁₂ heterocyclyloxy,C₁-C₃₀ heterocyclylalkyloxy, C₁-C₃₀ heterocyclylaminyl, C₅-C₃₀heterocyclylalkylaminyl, C₂-C₁₂ heterocyclylcarbonyl, C₃-C₃₀heterocyclylalkyl, C₁-C₁₃ heteroaryl, or C₃-C₃₀ heteroarylalkyl.

In some embodiments, X in the thiophene-based unit is O.

In some embodiments, the disclosed ECPs comprise a formula of

wherein n, and m are integers greater than 0.

In another aspect, an electrochromic polymer is provided. Theelectrochromic polymer includes a polymer backbone having one or moreMCLs and one or more Ars. The electrochromic polymer has a transmittanceof at least 60% in the visible light range (e.g., 450-750 nm) in aneutral state, and is colored and near-IR absorbing in an oxidizedstate.

In some embodiments, the electrochromic polymer is transparent in thevisible light range in the neutral state.

In some embodiments, the one or more MCLs and the one or more Ars arecoupled to each other alternatively or randomly such that a MCL ispartially conjugated with an Ar at meta positions of the MCL.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain features of various embodiments of the present technology areset forth with particularity in the appended claims. A betterunderstanding of the features and advantages of the technology will beobtained by reference to the following detailed description that setsforth illustrative embodiments, in which the principles of the inventionare utilized, and the accompanying drawings below. For the purpose ofillustrating the invention, the drawings show aspects of one or moreembodiments of the invention. However, it should be understood that thepresent invention is not limited to the precise arrangements andinstrumentalities shown in the drawings.

FIGS. 1(A)-(B) are diagrams representing the different color changingmechanisms of the disclosed ECP (FIG. 1(A)) compared to conventional ECP(FIG. 1(B)).

FIG. 2 is the CV data of an exemplary solid-state device using anexample ECP-1, according to one embodiment.

FIG. 3 is the switching kinetics of the exemplary solid-state deviceusing the example ECP-1 at 483 nm, according to one embodiment.

FIG. 4 are the absorbance spectra of the exemplary ECP-1 thin film atdifferent voltages, according to one embodiment.

FIG. 5 is the CV data of an exemplary solid-state device using anotherexample ECP-2, according to one embodiment.

FIG. 6 is the switching kinetics of the exemplary solid-state deviceusing the example ECP-2 at 550 nm, according to one embodiment.

FIG. 7 are the absorbance spectra of the exemplary ECP-2 thin film atdifferent voltages, according to one embodiment.

FIG. 8 is the CV data of an exemplary solid-state device using yetanother example ECP-3, according to one embodiment.

FIG. 9 is the switching kinetics of the exemplary solid-state deviceusing the example ECP-3 at 550 nm, according to one embodiment.

FIG. 10 are the absorbance spectra of the exemplary ECP-3 thin film atdifferent voltages, according to one embodiment.

FIG. 11 shows the absorbance spectra of the exemplary ECP-1 thin film atdifferent voltages, according to one embodiment.

FIG. 12 shows the absorbance spectra of the exemplary ECP-2 thin film atdifferent voltages, according to one embodiment.

FIG. 13 shows the absorbance spectra of the exemplary ECP-3 thin film atdifferent voltages, according to one embodiment.

DETAILED DESCRIPTION OF EMBODIMENTS

In the following description, certain specific details are set forth inorder to provide a thorough understanding of various embodiments of theinvention. However, one skilled in the art will understand that theinvention may be practiced without these details. Moreover, whilevarious embodiments of the invention are disclosed herein, manyadaptations and modifications may be made within the scope of theinvention in accordance with the common general knowledge of thoseskilled in this art. Such modifications include the substitution ofknown equivalents for any aspect of the invention in order to achievethe same result in substantially the same way.

Unless the context requires otherwise, throughout the presentspecification and claims, the word “comprise” and variations thereof,such as “comprises” and “comprising” are to be construed in an open,inclusive sense, that is as “including, but not limited to.” Recitationof numeric ranges of values throughout the specification is intended toserve as a shorthand notation of referring individually to each separatevalue falling within the range inclusive of the values defining therange, and each separate value is incorporated in the specification asit was individually recited herein. Additionally, the singular forms “a”“an”, and “the” include plural referents unless the context clearlydictates otherwise.

Reference throughout this specification to “one embodiment” or “anembodiment” means that a particular feature, structure, orcharacteristic described in connection with the embodiment is includedin at least one embodiment of the present invention. Thus, theappearances of the phrases “in one embodiment” or “in an embodiment” invarious places throughout this specification are not necessarily allreferring to the same embodiment, but may be in some instances.Furthermore, the particular features, structures, or characteristics maybe combined in any suitable manner in one or more embodiments.

The present disclosure is related to a new type of electrochromicpolymers. In some embodiments, the new type of electrochromic polymersmay exhibits colorless-to-colored anodically coloring. Theelectrochromic polymers are called anodically coloring conjugatedelectrochromic polymers (AC-ECPs) with a repeat unit comprising one ormore metal-conjugated linkers (MCLs) and one or more aromatic moieties(Ars), where meta-conjugation is introduced along the polymer backbonethrough the use of the MCL. Each of the one or more MCLs is partiallyconjugated with the one or more Ars at meta positions of the one or moreMCLs to form the polymer backbone of the electrochromic polymer.

As illustrated in FIG. 1 , conventional conjugated ECPs (FIG. 1(B)) arefully conjugated and have strong absorbance in the visible light regionand are thus colored in their neutral state, while when oxidized(oxidized state), their absorption is shifted toward near-IR region andthey become transmissive. However, the oxidized polymers still have weakabsorption in the visible light region, leading to residue colors. Onthe other hand, as illustrated for one example disclosed ECP in FIG.1(A), the ECP exhibits substantially no absorption after 400 nm in theneutral state and has several absorption peaks in visible light rangeand the near infrared range in the oxidized state, demonstratingcoloring in the visible light range and near-infrared absorbing.

The disclosed ECPs allows passing or blocking of visible light andnear-IR light to be synchronized, which is in one embodiment very usefulin an electrochromic window for the management of solar heat gain. Thedisclosed ECPs are transparent in the neutral state, and are colored andIR-absorbing in the oxidized state, which are highly desired in order toachieve a high optical contrast, a high transmittance and a synergisticsolar-heat gain.

The disclosed ECPs are transparent in the visible light region in theneutral state and are colored in the oxidized state. For example, thedisclosed ECPs may have a transmittance of at least 60% in the visiblelight range (e.g., 450-750 nm) in the neutral state. In someembodiments, the disclosed ECPs may have a transmittance of at least65%, 70%, 75%, 80%, 85%, 90%, 92%, 95%, 98%, or above in the range of450-750 nm in the neutral state. In some embodiments, the disclosed ECPsare transparent in the visible light range in the neutral state. In theoxidized state, the disclosed ECPs have absorption in the visible lightrange (e.g., about 360 to 750 nm) and the near-IR range (e.g., about 750to 1600 nanometers), thereby being colored and near-infrared absorbing.

The disclosed ECP has UV absorption. In some embodiments, theelectrochromic polymer has an absorption onset (

, the wavelength at higher than which the polymer has no photonabsorption) at 480 nm or less in the neutral state. In some embodiments,the electrochromic polymer has an absorption onset at 450 nm or less or400 nm or less in the neutral state. The absorption onset values of theneutral state spectra are defined as the x-intercept of the tangent lineon the inflection point for the absorption peak of the neutral statespectra. In some embodiments, the absorption maxima (

_(max), the wavelength at which the polymer has its strongest photonabsorption) are less than 420 nm in the neutral state. In someembodiments, the electrochromic polymer is colorless (e.g., noabsorbance in 400-750 nm) or yellow (e.g., tailing absorption in 400-500nm, or 400-480 nm, or 400-450 nm) in the neutral state and is coloredand visible and near-IR absorbing in the oxidized state. The oxidizedelectrochromic polymer has an absorption coefficient larger than 10⁴cm⁻¹ in the visible and/or near-IR region and thus colored in theoxidized state. In some embodiments, the disclosed AC-ECP has an energybandgap equal to or higher than 2.5 eV and less than 4.0 eV in theneutral state. In some embodiments, the disclosed AC-ECP has an energybandgap equal to or higher than 2.6, 2.7, 2.8, 2.9, or 3.0 eV and lessthan 4.0 eV in the neutral state.

Due to substantial lack of absorbance in the visible light range in theneutral state and high absorbance in the visible light range in theoxidized state, the disclosed ECPs demonstrate high optical contrast andhigh optical transmittance when comparing with conventional ECPs. Inspite of their high bandgaps, the disclosed ECPs have relatively lowoxidation potential in the ranges of 0.1-1.5 V inclusive versus Ag/AgClelectrode in some embodiments. The relatively low oxidation potentialcan benefit cycling durability of ECPs. Thus, the disclosed ECPs can besuccessfully incorporated into a device with a good cyclingstability/reliability and a high optical contrast.

The MCL comprises at least one of an aromatic ring structure, or a fusedaromatic ring structure, or the combinations thereof. The aromatic ringstructure comprises a benzene or heterocyclic structure. The fusedaromatic ring structure comprises a fused benzene structure or a fusedheterocyclic structures or a fused benzene and heterocyclic ringstructure. In some embodiments, the MCL comprises at least one ofbenzene, or naphthalene, or five-membered heterocycle, or benzene fusedfive-membered heterocycle, or a combination of these structures. Sidechains or aromatic side chains can also be introduced onto the MCL toadjust its performance, for example, solubility or processibility orstability.

In some embodiments, the MCLs and the Ars are arranged in an alternativeor random fashion with a general formula of

In the structure here, each of n and m₁, m₂, . . . , m_(n) is an integerhigher than 0. Ar is an aromatic moiety, which may include one or morearomatic ring structures. Each of the MCLs (or Ars) can be the same asor different from each other.

Meta-conjugation is introduced in the polymer backbone through the useof the one or more MCLs. Each of the one or more MCLs is partiallyconjugated in the polymer backbone by connecting with Ar(s) through itsmeta-positions. For example, the meta-positions are two positions of thearomatic ring structure or a fused aromatic ring structure of the MCLs.When the meta-positions are connected, the pi electrons from an aromaticring structure or a fused aromatic ring structure cannot be fullydelocalized to another adjacently-connected unit through p-orbitals.

In some embodiments, an aromatic core comprises a benzene ring structureor a five-membered heterocyclic structure, and the aromatic core issubstituted at meta-positions, which are the 1- and 3-positions on thearomatic ring. In some embodiments, the aromatic core structurecomprises naphthalene, and the aromatic core is substituted atmeta-positions, which are the 1- and 3-, or 1- and 4-, or 1- and6-positions on naphthalene. In some embodiments, the aromatic corestructure comprises benzene fused with a five-membered heterocycle, andthe aromatic core is substituted at meta-positions, which are the 1- and3-, or 1- and 5-positions on the benzene fused heterocycle.

Example Structures of the MCL and its Meta-Positions May Include

wherein X is S, Se, N, C, or O; R₁-R₁₂ is independently selected fromthe following substituents, including, but not limited to, hydrogen,C₁-C₃₀ alkyl, C₂-C₃₀ alkenyl, C₂-C₃₀ alkynyl, C₂-C₃₀ alkylcarbonyl,C₁-C₃₀ alkoxy, C₃-C₃₀ alkoxyalkyl, C₂-C₃₀ alkoxycarbonyl,C₄-C₃₀alkoxycarbonylalkyl, C₁-C₃₀ alkylthio, C₁-C₃₀ aminylcarbonyl,C₄-C₃₀ aminylalkyl, C₁-C₃₀ alkylaminyl, C₁-C₃₀ alkylsulfonyl, C₃-C₃₀alkylsulfonylalkyl, C₆-C₁₈ aryl, C₃-C_(1s) cycloalkyl, C₃-C₃₀cycloalkylaminyl, C₅-C₃₀ cycloalkylalkylaminyl, C₅-C₃₀ cycloalkylalkyl,C₅-C₃₀cycloalkylalkyloxy, C₁-C₁₂ heterocyclyl, C₁-C₁₂ heterocyclyloxy,C₁-C₃₀ heterocyclylalkyloxy, C₁-C₃₀ heterocyclylaminyl, C₅-C₃₀heterocyclylalkylaminyl, C₂-C₁₂ heterocyclylcarbonyl, C₃-C₃₀heterocyclylalkyl, C₁-C₁₃ heteroaryl, or C₃-C₃₀ heteroarylalkyl; and thewavy lines represent the meta-positions.

The Ar may include, but is not limited to, any one of a thiophene-basedunit, a furan-based unit, a selenophene-based unit, or a pyrrole-basedunit respectively with a formula of

or any combination thereof.

In the structures above, each of R₁₃ and R₁₄ is independently selectedfrom the following substituents, including, but not limited to,hydrogen, C₁-C₃₀ alkyl, C₂-C₃₀ alkenyl, C₂-C₃₀ alkynyl, C₂-C₃₀alkylcarbonyl, C₁-C₃₀ alkoxy, C₃-C₃₀ alkoxyalkyl, C₂-C₃₀ alkoxycarbonyl,C₄-C₃₀ alkoxycarbonylalkyl, C₁-C₃₀ alkylthio, C₁-C₃₀ aminylcarbonyl,C₄-C₃₀ aminylalkyl, C₁-C₃₀alkylaminyl, C₁-C₃₀ alkylsulfonyl, C₃-C₃₀alkylsulfonylalkyl, C₆-C₁₈ aryl, C₃-C₁₅ cycloalkyl, C₃-C₃₀cycloalkylaminyl, C₅-C₃₀ cycloalkylalkylaminyl, C₅-C₃₀ cycloalkylalkyl,C₅-C₃₀cycloalkylalkyloxy, C₁-C₁₂ heterocyclyl, C₁-C₁₂ heterocyclyloxy,C₁-C₃₀ heterocyclylalkyloxy, C₁-C₃₀ heterocyclylaminyl, C₅-C₃₀heterocyclylalkylaminyl, C₂-C₁₂ heterocyclylcarbonyl, C₃-C₃₀heterocyclylalkyl, C₁-C₁₃ heteroaryl, or C₃-C₃₀ heteroarylalkyl.

An example thiophene-based unit may include, but is not limited to, theformula of

or a combination thereof.

In the structures above, X is S, Se, N, C, or O; each of R₁₅-R₁₈ isindependently selected from the following substituents, including, butnot limited to, hydrogen, C₁-C₃₀ alkyl, C₂-C₃₀ alkenyl, C₂-C₃₀ alkynyl,C₂-C₃₀ alkylcarbonyl, C₁-C₃₀ alkoxy, C₃-C₃₀ alkoxyalkyl, C₂-C₃₀alkoxycarbonyl, C₄-C₃₀ alkoxycarbonylalkyl, C₁-C₃₀ alkylthio, C₁-C₃₀aminylcarbonyl, C₄-C₃₀ aminylalkyl, C₁-C₃₀ alkylaminyl, C₁-C₃₀alkylsulfonyl, C₃-C₃₀ alkylsulfonylalkyl, C₆-C₁₈ aryl, C₃-C₁₅cycloalkyl, C₃-C₃₀ cycloalkylaminyl, C₅-C₃₀cycloalkylalkylaminyl, C₅-C₃₀cycloalkylalkyl, C₅-C₃₀cycloalkylalkyloxy, C₁-C₁₂ heterocyclyl, C₁-C₁₂heterocyclyloxy, C₁-C₃₀ heterocyclylalkyloxy, C₁-C₃₀ heterocyclylaminyl,C₅-C₃₀ heterocyclylalkylaminyl, C₂-C₁₂ heterocyclylcarbonyl, C₃-C₃₀heterocyclylalkyl, C₁-C₁₃ heteroaryl, or C₃-C₃₀ heteroarylalkyl.

In some embodiments, the X in the thiophene-based unit is O.

By introducing meta-conjugation into the ECP polymer backbone, theelectronic conjugation along the polymer backbone is interrupted andleads to a high bandgap (>2.0 eV). Thus, the disclosed ECP appearshighly transmissive (or even transparent) in the neutral state.Oxidation of the ECP results in a lower bandgap (<1.5 eV), and theabsorbance of the polymer is red-shifted from UV region to visible andnear-IR region. Thus, the polymer becomes highly colored.

The Ar might include one or more aromatic ring structures or fusedaromatic ring structures. By controlling the types and amounts of theAr, the redox potentials of the disclosed ECP can be easily tuned whilemaintaining its high transparency within the visible light range in theneutral state. For example, more electron-rich units (e.g.,dioxythiophenes) can be introduced onto the backbone to make the polymermore favorable to be oxidized, thereby decreasing its onset potentialand improving its electrochemical stability and electrochromic cyclingstability. The redox potentials of the disclosed ECP can also beadjusted by varying substituents on MCLs (e.g., introducing alkoxy sidechains).

The disclosed ECPs can be dissolved in a solvent, for example, tolueneor p-xylene, which can be used for solution-processable film castingprocesses. By controlling the concentration of the polymer solution, apolymer thin film with a controllable thickness can be obtained.Furthermore, the excellent solubility makes the disclosed ECPscompatible with various casting methods, for example, spin-coating,spray-coating, and drop-casting. Manufacturing friendly process makesits extended applications feasible.

Examples are shown in the following.

EMBODIMENTS Example 1 ECP-1

In some embodiments, the disclosed ECP-1 comprises a formula of

ECP-1 is synthesized by first preparing a benzene reaction unit and thenpolymerizing the benzene reaction unit with a ProDOT unit. The detailmethod includes the following steps:

Step 1-1: preparing a benzene reaction unit (compound 1)

Compound 2, benzyltrimethylammonium tribromide, and CaCO₃ are dissolvedin methanol/dichloromethane (⅖, v/v). The mixture is stirred at roomtemperature for 24 hours. The reaction mixture is concentrated underreduced pressure, and the residue is dissolved in chloroform. Thesolution is washed with deionized water, dried over sodium sulfate, andthe solvent is removed in vacuum.

Step 1-2: polymerization

The benzene reaction unit (compound 1), ProDOT (compound 3), andPd2(dba)₂, tris(2-methoxyphenyl)phosphine, Cs₂CO₃, and PviOH are addedin a dry Schlenk tube under N₂. The Schlenk tube is then put under highvacuum followed by backfilling with nitrogen twice. Toluene is added tothe solvent, and the reaction mixture is subjected to three-pump-thawcycle backfilling with nitrogen. The reaction mixture is heated at 100°C. for one day. Stop the reaction and add chloroform. Wash the reactionmixture with deionized water and extract the aqueous with chloroform.The combined organic phase is dried over anhydrous sodium sulfate, andthen it is filtered and dried in vacuum. The solid is dissolved inchloroform, and the solution is poured into vigorously stirred methanolfor precipitation. Filter to obtain the polymer.

The obtained ECP-1 has an oxidation potential of around 0.6 V (vs.Ag/AgCl) and an energy bandgap higher than 2.8 eV. It is fabricated intoa solid-state electrochromic device (ECD) with ECP-1 used as theelectrochromic layer, 1M of LiPF₆ in PEGMEA as the electrolyte, andVO_(x) as the ion storage layer. The solid-state ECD can be stablyswitched between −0.2 V to 1.0 V (FIG. 2 ). The neutral state andoxidized state absorption spectra of the ECP-1 thin film are shown inFIG. 4 with λ_(c) of 400 nm when the absorption onset is “defined as thex-intercept of the tangent line on the inflection point for theabsorption peak of the neutral state spectra”. Referring to FIG. 11 ,the absorption onset is 480 nm when the absorption onset is defined as“the wavelength at higher than which the polymer has no photonabsorption.” The solid-state ECD is highly transparent with atransmittance up to 90% in neutral state at around 550 nm (−0.2 V) (FIG.3 ), and displays a bright red color when the ECP-1 is oxidized with oneabsorption peak at around 487 nm and elevated absorption spectra at IRrange, around 900 to 1100 nm (FIG. 4 ). The optical contrast of thesolid-state ECD is about 69% (as shown in FIG. 3 ).

Example 2 ECP-2

In some embodiments, the disclosed ECP-2 has a formula of

The ECP-2 is synthesized by preparing a benzene-containing reaction unitand then polymerizing it with a dimer unit. The detail method includesthe following steps:

Step 2-1: preparing a benzene-containing reaction unit (compound 4) bytwo steps.

Compound 5 and p-toluenesulfonic acid are dissolved in acetonitrile.Subsequently, N-bromosuccinimide is added, and the mixture is agitatedovernight. The suspension is filtered to get the desired product. Theproduct compound 6 is a white solid.

Compound 6 is dissolved in DMF under N₂. K₂CO₃ is added to the solution,and the reaction mixture is stirred for 15 mins, after which2-ethylhexyl bromide is added. The reaction mixture is stirred at 100°C. overnight. The reaction is stopped and cooled down to roomtemperature. The solvent is removed in vacuum, and the residue isdissolved in diethyl ether. The organic phase is washed with water, andthe aqueous phases are extracted with ethyl acetate. The combinedorganic phases are dried, and the volatiles is removed by vacuum. Thecrude is passed through a small silica column, and the solvent is driedin vacuum to get the compound 4 as a yellow oil.

Step 2-2: polymerization: The polymerization method is similar to thatin step 1-1, only differs on the reaction units. The reaction units hereare the benzene-containing reaction unit (compound 4) and a dimer unit(compound 7) with a structure of

The obtained ECP-2 has an oxidation potential of around 1.0 V (vs.Ag/AgCl) and an energy bandgap of higher than 2.8 eV. The ECP-2 isfabricated into a solid-state ECD with ECP-2 used as the electrochromiclayer, 1M of LiPF₆ in PEGMEA as the electrolyte, and VO_(x) as the ionstorage layer. The solid-state ECD can be stably switched between −0.4 Vto 1.2 V (FIG. 5 ). The neutral state and oxidized absorbance spectra ofthe ECP−2 are shown in FIG. 7 with λ_(c) of 450 nm when the absorptiononset is “defined as the x-intercept of the tangent line on theinflection point for the absorption peak of the neutral state spectra”and λ_(max) of 392 nm. Referring to FIG. 12 , the absorption onset is514 nm when the absorption onset is defined as “the wavelength at higherthan which the polymer has no photon absorption.” The solid-state ECDshows a high transparency with transmittance as high as 96% in theneutral state (FIG. 6 ), and switches to a bright blue color when ECP-2is oxidized with one absorption peak at about 600 nm and another boarderabsorption band at the near-IR region, around 900-1100 nm (FIG. 7 ). Theoptical contrast of the solid-state ECD is about 89% (FIG. 6 ).

Example 3 ECP-3

In some embodiments, the disclosed ECP-3 has a formula of

The ECP-3 is synthesized by first preparing a substituted benzenereaction unit and then polymerizing it with an acyclic dioxythiophene(AcDOT) unit. The detail method includes the following steps:

Step 3-1: same as step 2-1.

Step 3-2: polymerization: The polymerization method is similar to thatin step 1-1, only differs on the reaction units. The reaction units hereare the substituted benzene reaction unit (compound 4) and AcDOT(compound 8) with a structure of

The obtained ECP-3 has a oxidation potential around 0.95 V (vs. Ag/AgCl)and an energy bandgap higher than 3.1 eV. The ECP-3 is fabricated into asolid-state ECD with ECP-3 used as the electrochromic layer, 1M of LiPF₆in PEGMEA as the electrolyte, and VO_(x) as the ion storage layer. Thesolid-state ECD can be stably switched between −0.6 V to 1.7 V (FIG. 8). The neutral state and oxidized state absorbance spectra of the ECP-3are shown in FIG. 10 with λ_(c) of 394 nm when the absorption onset is“defined as the x-intercept of the tangent line on the inflection pointfor the absorption peak of the neutral state spectra” and λ_(max) of 350nm. Referring to FIG. 13 , the absorption onset is 410 nm when theabsorption onset is defined as “the wavelength at higher than which thepolymer has no photon absorption.” The solid-state ECD shows hightransparency with transmittance as high as 94% at neutral state at 550nm (FIG. 9 ), and switches to bright red color when ECP-3 is oxidizedwith one absorption peak at around 546 nm and another broader absorptionband at the wavelength around 800-1100 nm (FIG. 10 ). The opticalcontrast of the solid-state ECD is 87% (FIG. 9 ).

Example 4 ECP-4

In some embodiments, the disclosed ECP-4 has a formula of

ECP-4 is synthesized by preparing a benzene-containing reaction unit andpolymerizing it with a ProDot unit. The detail method includes thefollowing steps:

Step 4-1: the same as Step 2-1

Step 4-2: polymerization: The polymerization method is similar to thatin step 1-1, only differs on the reaction units. The reaction units hereare benzene-containing reaction unit (compound 4) and 3,4-Ethylenedioxythiophene (EDOT, compound 9) with a structure of

Example 5 ECP-5

In some embodiments, the disclosed ECP has a formula of

The ECP-5 is synthesized by preparing a naphthalene-containing reactionunit and then polymerizing it with an AcDOT unit. The detail methodincludes the following steps:

Step 5-1: preparing naphthalene-containing reaction unit (compound 10)by two steps.

To a solution of compound 11 in dichloromethane was added dropwise asolution of bromine in dichloromethane over 15 minutes at −78° C. Thereaction mixture is stirred for 2 hours at −78° C. and then warmedgradually to room temperature and stay at room temperature for anadditional 2 hours. The excess bromine was quenched by saturated aqueoussodium sulfite solution and stirred for 2 hours at room temperature.After extraction with dichloromethane, the combined organic layer waswashed with brine, dried over sodium sulfate, and concentrated invacuum.

Compound 12 is dissolved in DMF under N₂, K₂CO₃ is added to thesolution, and the reaction mixture is stirred for 15 minutes, afterwhich 2-ethylexyl bromide is added. The reaction mixture is stirred at100° C. overnight. The reaction is stopped and cooled down to roomtemperature. The solvent is removed in vacuum, and the residue isdissolved in diethyl ether. The organic phase is washed with water, andthe aqueous phases are extracted with ethyl acetate. The combinedorganic phases are dried by vacuum.

Step 5-2: polymerization: The polymerization method is similar to thatin step 1-1, only differs on the reaction units. The reaction units hereare the naphthalene-containing reaction unit (compound 10) and AcDOT(compound 8).

Example 6 ECP-6

In some embodiments, the disclosed ECP has a formula of

The ECP-6 is synthesized by a carbazole reaction unit polymerized with aProDot unit. The detail method includes the following step:

Step 6-1: polymerization: polymerization method is similar to that instep 1-1, only differs on the reaction units. The reaction units hereare the carbazole reaction unit (compound 13) with a structure of

Example 7 ECP-7

In some embodiments, the disclosed ECP has a formula of

The ECP-7 is synthesized by the following reaction.

1,5-dibromo-2,4-bis(hexyloxy)benzene (1.0 eq), 3,4-dimethylthiophene(1.0 eq), K₂CO₃ (2.6 eq.), PivOH (0.3 eq.) and Pd(OAc)₂ (0.02 eq.) areadded to a schlenk tube. The tube is kept under vacuum for about 5minutes and then the solution is purged with N₂. The process describedabove is repeated for three cycles. Then, nitrogen degassed solventDimethylacetamide (DMAc) is added into the tube and the mixture isheated to 120° C. for 12 hrs under nitrogen. Transfer the hot reactionmixture to a 1:1 mixture solvent of CH₃OH and 1M HCl with stirring.Filter to get the solid. The solid is dissolved in chloroform and washedwith 1M HCl solution. The organic phase is concentrated and precipitatedwith CH₃OH, which is filtere and dried to get off-white solid. Yield70-100%.

In some embodiments, the disclosed ECP has a formula of

wherein n and m are integers greater than 0.

In another aspect, the disclosed polymers can have fluorescent emissionand can be applied to fluorescent products.

The foregoing description of the present disclosure has been providedfor the purposes of illustration and description. It is not intended tobe exhaustive or to limit the disclosure to the precise forms disclosed.The breadth and scope of the present disclosure should not be limited byany of the above-described exemplary embodiments. Many modifications andvariations will be apparent to the practitioner skilled in the art. Themodifications and variations include any relevant combination of thedisclosed features. The embodiments were chosen and described in orderto best explain the principles of the disclosure and its practicalapplication, thereby enabling others skilled in the art to understandthe disclosure for various embodiments and with various modificationsthat are suited to the particular use contemplated. It is intended thatthe scope of the disclosure be defined by the following claims and theirequivalence.

What is claimed is:
 1. An electrochromic polymer, consisting of: arepeat unit comprising one or more meta-conjugated linkers (MCLs) andone or more aromatic moieties (Ars), wherein each of the one or moreMCLs is partially conjugated with the one or more Ars at meta positionsof the one or more MCLs to form a polymer backbone of the electrochromicpolymer, and wherein the electrochromic polymer is colorless iscolorless in a neutral state, wherein each of the one or more MCLs andcorresponding meta positions comprise one of the following formulas:

wherein X is S, Se, N, C, or O; each of R₁-R₁₂ is independently selectedfrom one of hydrogen, C₁-C₃₀ alkyl, C₂-C₃₀ alkenyl, C₂-C₃₀ alkynyl,C₂-C₃₀ alkylcarbonyl, C₁-C₃₀ alkoxy, C₃-C₃₀ alkoxyalkyl, C₂-C₃₀alkoxycarbonyl, C₄-C₃₀ alkoxycarbonylalkyl, C₁-C₃₀ alkylthio, C₁-C₃₀aminylcarbonyl, C₄-C₃₀ aminylalkyl, C₁-C₃₀ alkylaminyl, C₁-C₃₀alkylsulfonyl, C₃-C₃₀ alkylsulfonylalkyl, C₆-C₁₈ aryl, C₃-Ciscycloalkyl, C₃-C₃₀ cycloalkylaminyl, C₅-C₃₀ cycloalkylalkylaminyl,C₅-C₃₀ cycloalkylalkyl, C₅-C₃₀ cycloalkylalkyloxy, C₁-C₁₂ heterocyclyl,C₁-C₁₂ heterocyclyloxy, C₁-C₃₀ heterocyclylalkyloxy, C₁-C₃₀heterocyclylaminyl, C₅-C₃₀ heterocyclylalkylaminyl, C₂-C₁₂heterocyclylcarbonyl, C₃-C₃₀ heterocyclylalkyl, C₁-C₁₃ heteroaryl, orC₃-C₃₀ heteroarylalkyl; and each of the wavy lines represents one of themeta positions, and wherein each of the one or more Ars comprises one ofa thiophene-based unit, a furan-based unit, a selenophene-based unit, ora pyrrole-based unit respectively with a formula of:

or a combination thereof, wherein each of R₁₃ and R₁₄ is independentlyselected from one of hydrogen, C₁-C₃₀ alkyl, C₂-C₃₀ alkenyl, C₂-C₃₀alkynyl, C₂-C₃₀ alkylcarbonyl, C₁-C₃₀ alkoxy, C₃-C₃₀ alkoxyalkyl, C₂-C₃₀alkoxycarbonyl, C₄-C₃₀ alkoxycarbonylalkyl, C₁-C₃₀ alkylthio, C₁-C₃₀aminylcarbonyl, C₄-C₃₀ aminylalkyl, C₁-C₃₀ alkylaminyl, C₁-C₃₀alkylsulfonyl, C₃-C₃₀ alkylsulfonylalkyl, C₆-C₁₈ aryl, C₃-Ciscycloalkyl, C₃-C₃₀ cycloalkylaminyl, C₅-C₃₀ cycloalkylalkylaminyl,C₅-C₃₀ cycloalkylalkyl, C₅-C₃₀ cycloalkylalkyloxy, C₁-C₁₂ heterocyclyl,C₁-C₁₂ heterocyclyloxy, C₁-C₃₀ heterocyclylalkyloxy, C₁-C₃₀heterocyclylaminyl, C₅-C₃₀ heterocyclylalkylaminyl, C₂-C₁₂heterocyclylcarbonyl, C₃-C₃₀ heterocyclylalkyl, C₁-C₁₃ heteroaryl, orC₃-C₃₀ heteroarylalkyl.
 2. The electrochromic polymer of claim 1,wherein the electrochromic polymer has an absorption maximum (λ_(max))at about or smaller than 392 nm in the neutral state.
 3. Theelectrochromic polymer of claim 2, wherein the electrochromic polymer iscolored and visible absorbing in an oxidized state.
 4. Theelectrochromic polymer of claim 3, wherein the electrochromic polymer isfurther near-infrared absorbing in the oxidized state.
 5. Theelectrochromic polymer of claim 4, wherein the oxidized electrochromicpolymer has an absorption coefficient larger than 10⁴ cm⁻¹ in theoxidized state.
 6. The electrochromic polymer of claim 1, wherein theelectrochromic polymer has an oxidation potential in the ranges of0.1-1.5 V inclusive versus Ag/AgCl electrode.
 7. The electrochromicpolymer of claim 1, wherein the one or more MCLs and the one or more Arsare arranged in an alternative fashion with a formula of

wherein each of n and m₁, m₂, . . . , m_(n) is an integer greater than0.
 8. The electrochromic polymer of claim 1, wherein the thiophene-basedunit comprises a formula of

or a combination thereof, wherein X is S, Se, N, C, or O; each ofR₁₅-R₁₈ is independently selected from one of hydrogen, C₁-C₃₀ alkyl,C₂-C₃₀ alkenyl, C₂-C₃₀ alkynyl, C₂-C₃₀ alkylcarbonyl, C₁-C₃₀ alkoxy,C₃-C₃₀ alkoxyalkyl, C₂-C₃₀ alkoxycarbonyl, C₄-C₃₀ alkoxycarbonylalkyl,C₁-C₃₀ alkylthio, C₁-C₃₀ aminylcarbonyl, C₄-C₃₀ aminylalkyl, C₁-C₃₀alkylaminyl, C₁-C₃₀ alkylsulfonyl, C₃-C₃₀ alkylsulfonylalkyl, C₆-C₁₈aryl, C₃-C₁₅ cycloalkyl, C₃-C₃₀ cycloalkylaminyl, C₅-C₃₀cycloalkylalkylaminyl, C₅-C₃₀ cycloalkylalkyl, C₅-C₃₀cycloalkylalkyloxy, C₁-C₁₂ heterocyclyl, C₁-C₁₂ heterocyclyloxy, C₁-C₃₀heterocyclylalkyloxy, C₁-C₃₀ heterocyclylaminyl, C₅-C₃₀heterocyclylalkylaminyl, C₂-C₁₂ heterocyclylcarbonyl, C₃-C₃₀heterocyclylalkyl, C₁-C₁₃ heteroaryl, or C₃-C₃₀ heteroarylalkyl; Y isany one or more of Ars, or aromatic ring structures, or fused aromaticring structures, or a combinations thereof.
 9. The electrochromicpolymer of claim 8, wherein X in the thiophene-based unit is O.
 10. Theelectrochromic polymer of claim 1, wherein the electrochromic polymercomprises a formula of

wherein n and m are integers greater than
 0. 11. An electrochromicpolymer, consisting of: a repeat unit comprising one or moremeta-conjugated linkers (MCLs) and one or more aromatic moieties (Ars),wherein each of the one or more MCLs is partially conjugated with theone or more Ars at meta positions of the one or more MCLs to form apolymer backbone of the electrochromic polymer, wherein theelectrochromic polymer has an absorption onset at 410 nm or less in aneutral state, wherein the absorption onset indicates a wavelength athigher than which the electrochromic polymer has no photon absorption,wherein each of the one or more MCLs and corresponding meta positionscomprise one of the following formulas:

wherein X is S, Se, N, C, or O; each of R₁-R₁₂ is independently selectedfrom one of hydrogen, C₁-C₃₀ alkyl, C₂-C₃₀ alkenyl, C₂-C₃₀ alkynyl,C₂-C₃₀ alkylcarbonyl, C₁-C₃₀ alkoxy, C₃-C₃₀ alkoxyalkyl, C₂-C₃₀alkoxycarbonyl, C₄-C₃₀ alkoxycarbonylalkyl, C₁-C₃₀ alkylthio, C₁-C₃₀aminylcarbonyl, C₄-C₃₀ aminylalkyl, C₁-C₃₀ alkylaminyl, C₁-C₃₀alkylsulfonyl, C₃-C₃₀ alkylsulfonylalkyl, C₆-C₁₈ aryl, C₃-Ciscycloalkyl, C₃-C₃₀ cycloalkylaminyl, C₅-C₃₀ cycloalkylalkylaminyl,C₅-C₃₀ cycloalkylalkyl, C₅-C₃₀ cycloalkylalkyloxy, C₁-C₁₂ heterocyclyl,C₁-C₁₂ heterocyclyloxy, C₁-C₃₀ heterocyclylalkyloxy, C₁-C₃₀heterocyclylaminyl, C₅-C₃₀ heterocyclylalkylaminyl, C₂-C₁₂heterocyclylcarbonyl, C₃-C₃₀ heterocyclylalkyl, C₁-C₁₃ heteroaryl, orC₃-C₃₀ heteroarylalkyl; and each of the wavy lines represents one of themeta positions, and wherein each of the one or more Ars comprises one ofa thiophene-based unit, a furan-based unit, a selenophene-based unit, ora pyrrole-based unit respectively with a formula of:

or a combination thereof, wherein each of Rn and R₁₄ is independentlyselected from one of hydrogen, C₁-C₃₀ alkyl, C₂-C₃₀ alkenyl, C₂-C₃₀alkynyl, C₂-C₃₀ alkylcarbonyl, C₁-C₃₀ alkoxy, C₃-C₃₀ alkoxyalkyl, C₂-C₃₀alkoxycarbonyl, C₄-C₃₀ alkoxycarbonylalkyl, C₁-C₃₀ alkylthio, C₁-C₃₀aminylcarbonyl, C₄-C₃₀ aminylalkyl, C₁-C₃₀ alkylaminyl, C₁-C₃₀alkylsulfonyl, C₃-C₃₀ alkylsulfonylalkyl, C₆-C₁₈ aryl, C₃-C₁₅cycloalkyl, C₃-C₃₀ cycloalkylaminyl, C₅-C₃₀ cycloalkylalkylaminyl,C₅-C₃₀ cycloalkylalkyl, C₅-C₃₀ cycloalkylalkyloxy, C₁-C₁₂ heterocyclyl,C₁-C₁₂ heterocyclyloxy, C₁-C₃₀ heterocyclylalkyloxy, C₁-C₃₀heterocyclylaminyl, C₅-C₃₀ heterocyclylalkylaminyl, C₂-C₁₂heterocyclylcarbonyl, C₃-C₃₀ heterocyclylalkyl, C₁-C₁₃ heteroaryl, orC₃-C₃₀ heteroarylalkyl.
 12. The electrochromic polymer of claim 11,wherein the electrochromic polymer has an absorption maximum (λ_(max))at about or smaller than 392 nm in the neutral state.
 13. Theelectrochromic polymer of claim 12, wherein the electrochromic polymeris colored and visible absorbing in an oxidized state.
 14. Theelectrochromic polymer of claim 11, wherein the one or more MCLs and theone or more Ars are arranged in an alternative fashion with a formula of

wherein each of n and m₁, m₂, . . . , m_(n) is an integer greater than0.
 15. The electrochromic polymer of claim 11, wherein thethiophene-based unit comprises a formula of

or a combination thereof, wherein X is S, Se, N, C, or O; each ofR₁₅-R₁₈ is independently selected from one of hydrogen, C₁-C₃₀ alkyl,C₂-C₃₀ alkenyl, C₂-C₃₀ alkynyl, C₂-C₃₀ alkylcarbonyl, C₁-C₃₀ alkoxy,C₃-C₃₀ alkoxyalkyl, C₂-C₃₀ alkoxycarbonyl, C₄-C₃₀ alkoxycarbonylalkyl,C₁-C₃₀ alkylthio, C₁-C₃₀ aminylcarbonyl, C₄-C₃₀ aminylalkyl, C₁-C₃₀alkylaminyl, C₁-C₃₀ alkylsulfonyl, C₃-C₃₀ alkylsulfonylalkyl, C₆-C₁₈aryl, C₃-C₁₅ cycloalkyl, C₃-C₃₀ cycloalkylaminyl, C₅-C₃₀cycloalkylalkylaminyl, C₅-C₃₀ cycloalkylalkyl, C₅-C₃₀cycloalkylalkyloxy, C₁-C₁₂ heterocyclyl, C₁-C₁₂ heterocyclyloxy, C₁-C₃₀heterocyclylalkyloxy, C₁-C₃₀ heterocyclylaminyl, C₅-C₃₀heterocyclylalkylaminyl, C₂-C₁₂ heterocyclylcarbonyl, C₃-C₃₀heterocyclylalkyl, C₁-C₁₃ heteroaryl, or C₃-C₃₀ heteroarylalkyl; Y isany one or more of Ars, or aromatic ring structures, or fused aromaticring structures, or a combinations thereof.
 16. The electrochromicpolymer of claim 15, wherein X in the thiophene-based unit is O.
 17. Theelectrochromic polymer of claim 11, wherein the electrochromic polymercomprises a formula of

wherein n and m are integers greater than 0.